//
// Created by test on 22-11-28.
//
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<stdlib.h>
#include<assert.h>
#include<string.h>
#include<stdio.h>
#include<pthread.h>
#include<sys/epoll.h>
#include<fcntl.h>
#include<errno.h>
#define MAX_EVENT_NUMBER 1024
#define BUF_SIZE 1024
struct fds{
    int epollfd;
    int sockfd;
};
int setnonblocking(int fd){
    int old_option=fcntl(fd,F_GETFL);
    int new_option=old_option|O_NONBLOCK;
    fcntl(fd,F_SETFL,new_option);
    return old_option;
}
void addfd(int epollfd,int fd,bool oneshot){
    epoll_event event;
    event.data.fd=fd;
    event.events=EPOLLIN|EPOLLET;
    if(oneshot){
        event.events|=EPOLLONESHOT;
    }
    epoll_ctl(epollfd,EPOLL_CTL_ADD,fd,&event);
    setnonblocking(fd);
}
void reset_oneshot(int epollfd,int fd){
    epoll_event event;
    event.data.fd=fd;
    event.events=EPOLLIN|EPOLLET|EPOLLONESHOT;
    epoll_ctl(epollfd,EPOLL_CTL_MOD,fd,&event);
}
void *worker(void* arg){
    int sockfd=((fds*)arg)->sockfd;
    int epollfd=((fds*)arg)->epollfd;
    printf("start new thread to receive data on fd:%d\n",sockfd);
    char buf[BUF_SIZE];
    memset(buf,'\0',BUF_SIZE);
    while(1){
        int ret=recv(sockfd,buf,BUF_SIZE-1,0);
        if(ret==0){
            close(sockfd);
            printf("foreiner closed the connection\n");
            break;
        }
        else if(ret<0){
            if(errno==EAGAIN){
                reset_oneshot(epollfd,sockfd);
                printf("read later\n");
                break;
            }
        }
        else{
            printf("get content:%s\n",buf);
            sleep(5);
        }
    }
    printf("end thread receiving data on fd:%d\n",sockfd);
}
int main(int argc,char* argv[]){
    if(argc<=2){
        printf("error");
        return 1;
    }
    const char* ip=argv[1];
    int port=atoi(argv[2]);
    int ret=0;
    struct sockaddr_in address;
    bzero(&address,sizeof(address));
    address.sin_family=AF_INET;
    address.sin_port=htons(port);
    inet_pton(AF_INET,ip,&address.sin_addr);
    int listenfd=socket(PF_INET,SOCK_STREAM,0);
    assert(listenfd>=0);
    ret=bind(listenfd,(struct sockaddr*)&address,sizeof(address));
    assert(ret!=-1);
    ret=listen(listenfd,5);
    assert(ret!=-1);
    epoll_event events[MAX_EVENT_NUMBER];
    int epollfd=epoll_create(5);
    assert(epollfd!=-1);
    addfd(epollfd,listenfd,false);
    while(1){
        ret=epoll_wait(epollfd,events,MAX_EVENT_NUMBER,-1);
        if(ret<0){
            printf("epoll failure\n");
            break;
        }
        for(int i=0;i<ret;i++){
            int sockfd=events[i].data.fd;
            if(sockfd==listenfd){
                struct sockaddr_in client_address;
                socklen_t client_addrlength=sizeof(client_address);
                int connfd=accept(listenfd,(struct sockaddr*)&client_address,&client_addrlength);
                addfd(epollfd,connfd,true);
            }
            else if(events[i].events&EPOLLIN){
                pthread_t thread;
                fds fds_for_new_worker;
                fds_for_new_worker.sockfd=sockfd;
                pthread_create(&thread,NULL,worker,(void*)&fds_for_new_worker);
            }
            else{
                printf("something else happened\n");
            }
        }
    }
    close(listenfd);
    return 0;
}
